Agricultural harvester vehicles have unloading conveyors that are configured to unload grain collected in the grain tank on the agricultural harvester vehicles and to deposit that grain into a vehicle that is traveling alongside the harvester vehicle.
Agricultural harvester vehicles commonly use an auger as an unloading conveyor. In this arrangement, a steel tube encloses a helical auger—an Archimedes screw—that rotates to convey grain from the grain tank to the vehicle traveling alongside the harvester vehicle. One problem with auger conveyors is the sliding contact between the grain and the conveyor itself. The grain slides along the bottom of the steel tube and slides along the steel flight of the auger. Augers are limited in their capacity. They must be operated at a relatively slow speed so as not to damage the grain which requires a relatively large diameter tube and helical auger if the unloading conveyors are to convey much grain.
As with all equipment, the capacity of agricultural harvester vehicles has been steadily increasing. This has occurred by increasing the speed of the harvester vehicle as it travels through the field, and also by increasing the width of the swath. The latter is provided by increasing the width of the harvesting head of the agricultural harvester vehicle.
These changes have pointed to inherent flaws in the existing auger conveyors. The linear speedup travel through auger conveyors is limited, thus to increase the conveyor throughput the diameter of an auger conveyor must be increased. Since the swath width is greater, however, the length of the auger must also be increased. This greater diameter and greater length are particularly problematic due to the high side load and great weight they add to the harvester vehicle. Furthermore, a larger auger must carry a larger weight of grain.
For this reason, more recent designs have incorporated a belt conveyor which can be operated at higher linear speeds than an auger conveyor thereby permitting it to be built lighter and smaller than a corresponding auger conveyor of the same capacity even though it is longer than a typical auger conveyor.
One problem with belted conveyors is due to their greater length, light weight, and small cross-section: as the harvester vehicle travels through the field pitching, rolling, and yawing it can exert large forces on the base of the conveyor and on the support members as it tries to force the conveyor to pitch, roll, and yaw to match the harvester vehicle's motion.
For this reason, the applicants propose herein a method of suspending the conveyor from the harvester vehicle that permits the harvester vehicle to pitch, roll, and yaw as it follows the ground in the agricultural field while isolating the conveyor from excessive force communicated to the conveyor from the harvester vehicle itself. The system described herein permits relative motion between the harvester vehicle and the conveyor so that the harvester vehicle cannot apply excessive force to the unloading conveyor.
In the past, other arrangements have been provided to prevent damage to the unloading conveyor when an external force is applied to the unloading conveyor, such as a post, pole, tree, building, or other fixed structure. Typically, this is to prevent damage in the event that the operator drives the harvester vehicle (or at least the unloading conveyor of the vehicle) into a fixed obstruction. These devices permit the unloading conveyor to rotate and/or translate with respect to the harvester vehicle when the harvester vehicle drives the unloading conveyor into a fixed obstruction. They are not intended or designed to permit pitching, rolling, or yawing of the harvester vehicle with respect to the unloading conveyor (i.e. to permit relative movement between the harvester vehicle and the unloading conveyor) during normal operations as the harvester vehicle travels through the field.
One arrangement is shown in U.S. Pat. No. 6,718,746 to Hettiger. In this patent, a forage harvester vehicle has a long unloading spout that is driven by a motor and gear arrangement. The gear extends around the circumference of the tubular unloading spout and the motor drives this gear to drive the spout in rotation with respect to the harvester vehicle. A non-return friction overload clutch 48 is provided in the motor drive train to permit the spout to be pushed to one side if the spout encounters an obstacle in the field. If the spout hits an obstacle, the friction clutch 48 will yield, permitting the spout to turn about its vertical axis with respect to the harvester vehicle even though the motor that drives the gear is stopped.
A similar arrangement is shown in EP 1092342 A1 to Holger in which a hydraulic motor drives a circumferential gear to rotate the spout about a vertical axis. It has a pressure limiting valve between the feed line or return line for the hydraulic motor and the leakage line. This arrangement is a hydraulic analog of the friction clutch of the previous example, using hydraulic leakage to permit the spout to move with respect to the harvester vehicle once some force is applied to the spout. Again, this arrangement operates when some external force contacts the spout, pushing it to one side, and thereby causing the pressure in the motor to increase above a limiting value.
U.S. Pat. No. 7,393,275 B2 illustrates another example in which an unloading auger can be folded backward when the unloading auger contacts an immovable object. In this arrangement, the folding-backwards breaks the grain auger at its base, disconnecting the grain auger and disabling it.
U.S. Pat. No. 3,670,913 discloses a “break back system” similar to the previous system. It includes a hinge joint where the grain auger can fold or “break”. In addition, the auger has a support member that holds it up in the air that incorporates a breakaway mechanism 66. When the auger encounters an external object, this breakaway mechanism 66 disconnects completely from the harvester vehicle permitting the unloading auger to fold backwards with respect to the harvester vehicle.
In all of the above examples, a relief device operates when the unloading conveyor contacts some immovable object. The auger must either yield by folding backwards or be damaged. In all the cases, the force applied to the unloading conveyor must reach some threshold before a friction clutch, breakaway joint, or hydraulic pressure relief valve operates. They are designed to permit the unloading conveyor to survive when it accidentally contacts some object. In the case of the folding grain augers, this operation disables the unloading system. In each of the examples, the unloading system, when deflected, remains in a deflected and/or inoperable state until manually reset or reattached by the operator.
They are not configured to operate continuously to prevent the communication of excessive force from the harvester vehicle to the unloading conveyor as the harvester vehicle harvests in the field. It is an object of this invention to provide such a system.